As the key part of chip-scale atomic clocks (CSACs), the vapor cell directly determines the volume stability and power consumption of the CSAC. The reduction of the power consumption and CSAC volumes demands the manufacture of corresponding vapor cells. However, their micro-fabrication is challenging. This overview presents the research development of vapor cells of the past few years and analyzes the shortages of the current preparation technology. By comparing several different vapor cell preparation methods, we successfully realized the micro-fabrication of vapor cells using anodic bonding and deep silicon etching. The microelectromechanical system (MEMS) fabrication process is presented in detail. It is simple and avoids weak bonding strengths caused by alkali metal volatilization during anodic bonding under high temperatures. Finally, the vapor cell D2 line was characterized via optical absorption resonance. According to the results, the proposed method is suitable for CSAC.
zhang yanjun, Li Yunchao, Hu Xuwen, Zhang Lu, Liu Zhaojun, Zhang Kaifang, Mou Shihao, Zhang Shougang, Yan Shu-Bin. Micro-Fabrication Process of Vapor Cells for Chip-Scale Atomic Clock[J]. Chinese Optics Letters, 2019, 17(4): .
